The present invention relates to slide rails for vehicle seats and seats comprising such slide rails.
More particularly, the invention concerns a slide rail for a vehicle seat comprising:
first and second profiles intended to be attached one to the vehicle and the other to the seat, the first and second profiles being mounted in sliding relation to one another in a longitudinal direction in opposite first and second sliding directions corresponding respectively to movements of the seat forwards and rearwards,
a latch mounted on the second profile and moveable between firstly a locked position where said latch blocks the second profile in relation to the first profile, and secondly an unlocked position where said latch allows relative sliding between the first and second profiles, the latch being elastically biased towards its locked position,
first control means for moving the latch from its locked position to its unlocked position without blocking said latch in the unlocked position in order to adjust the seat position,
an unlocking device which is movable on the second profile between firstly a rest position where said unlocking device does not interfere with the latch and secondly an active position where said unlocking device places the latch in the unlocked position, the unlocking device being elastically biased towards its rest position and comprising retention means for holding said unlocking device in its active position when it has been placed in said active position, and the unlocking device also comprising an actuator finger designed to co-operate with at least one stop attached to said first profile to release the unlocking device, enabling it to return to its rest position when said unlocking device is in its active position and the first and second profiles move in relation to one another for the second sliding direction,
and second control means for moving the unlocking device from its rest position to its active position.
Slide rails of this types are used in particular to equip the front seats of two-door vehicles. To gain access to the rear seats of such a vehicle, the second means of control are actuated, generally by folding the seat back forward, then sliding the seat forward to a stop position. To return to its initial position, the seat is then slid back to a fixed position determined by the stop attached to the first profile: once arrived at this fixed position, the seat locks again in relation to the vehicle floor.
Document FR-A-2 746 354 describes an example of such a slide rail in which the stop consists of a spring rod attached to the first profile and designed to:
retract below the actuator finger of the unlocking device when the seat is moved forward,
and interfere with this actuator finger, forcing it to pivot to release the unlocking device, when the seat is moved to the back after having been slid forward.
The slide rail shown in this document generally gives satisfaction but nonetheless has the drawback that the spring rod constituting the stop is a relatively fragile piece which risks being damaged in particular due to external action and/or inappropriate action of the slide rail. In this case the function of the slide rail is deteriorated and its proper relocking is no longer guaranteed when the seat has been slid back after having been moved forward to gain access to the rear seats of the vehicle.
The purpose of the present invention is therefore to remedy these drawbacks.
To this end, according to the invention, a slide rail of the type concerned is characterized:
in that the retention means of the unlocking device comprise a hook element mounted pivotally on said unlocking device about a first transverse axis perpendicular to the longitudinal direction, said hook element being elastically biased in a first angular direction towards an engagement position where said hook element is able to co-operate, when the unlocking device is in its active position, with a complementary element fixedly attached to the second profile,
in that said hook element is movable in a second angular direction opposite the first angular direction from its first engagement position to a retracted position where said hook element does not co-operate with the complementary element,
in that the actuator finger is mounted pivoting on the hook element about a second transverse axis parallel to the first transverse axis, the actuator finger being elastically biased in the second angular direction towards an active position where said actuator finger is positioned to interfere with the stop of the first profile, the hook element co-operating with the actuator finger to allow only a pivoting of the actuator finger in the first angular direction from the active position of said actuator finger,
in that the first and second angular directions are selected so that the stop of the second profile biases the actuator finger in the second angular direction when said actuator finger is in the active position and meets said stop of the first profile while the first and second profiles move in relation to each other in the second sliding direction, the actuator finger then driving the hook element in the first angular direction up to its retracted position,
and in that the stop of the first profile is designed to co-operate with the actuator finger by a cam effect by moving said actuator finger in the first angular direction from its active position in relation to the hook element when said actuator finger meets said stop of the first profile, being in its active position, while the first and second profiles move in relation to each other in the first sliding direction so that said actuator finger can then pass beyond the stop of the first profile.
Thanks to these arrangements it is no longer necessary to rely on the flexibility of the stop, so that a more solid stop can be used than the simple spring blade of the prior art.
In preferred embodiments of the invention, where applicable also one and/or the other of the following arrangements may be used:
the stop of the first profile is rigid;
the first profile has approximately a U-shaped section with a horizontal web and two vertical side wings, the stop being constituted by a stamping arranged locally in the web of the first profile,
the unlocking device comprises a traveler which is slidingly mounted in the longitudinal direction on the second profile between positions corresponding to the rest and active positions of the unlocking device, the hook element being mounted pivoting on this traveler and said traveler co-operating by cam effect with a control finger linked to the latch in order to move said latch into its unlocked position when the unlocking device is in its active position,
the latch is an elastic metal part contained in an inner hollow space delimited by the first and second profiles, said latch comprising a free folded end forming said control finger,
the second profile has approximately a U-shaped cross-section with a horizontal web and two vertical side wings, the traveler being mounted on the web of the second profile outside the slide rail, said traveler being linked to the hook element through a longitudinal slot arranged in the web of the second profile, the hook element and the actuator finger being located in an inner hollow space delimited by the first and second profiles and being linked to the traveler through a longitudinal slot arranged in the web of the second profile, said longitudinal slot being also traversed by the control finger of the latch,
the hook element comprises a free end bearing a hook which projects towards the web of the second profile and which is designed to penetrate into a recess belonging to said web of the second profile, said hook being in the slot of the web of the second profile when the unlocking device is in the rest position, and said free end of the hook element having an inclined cam surface which is designed to co-operate with the web of the second profile at one of the slot of said web, repelling the hook element to its retracted position when the unlocking device is moved from its rest position to its active position,
the unlocking device comprises a spring with a hook branch which is linked to the actuator finger and which penetrates into an arc-shaped slot arranged in the hook element, said arc-shaped slot being centered on the second transverse axis and being arranged to allow the actuator finger to move in the first angular direction in relation to the hook element from the active position of said actuator finger, said hook branch exerting on the actuator finger and hook element a force oriented along a line passing between the first and second transverse axes so as to bias the hook element in a first angular direction and the actuator finger in the second angular direction.
Another object of the invention is a vehicle seat comprising a seat base slidingly mounted longitudinally by at least one slide rail as defined above.
Finally, another object of the invention is a vehicle seat comprising a seat base mounted sliding longitudinally by a first slide rail as defined above and a second slide rail also comprising first and second profiles and a latch moveable between locked and unlocked positions, the seat base being fixed to the second profiles of the slide rails, the traveler of the first slide rail being linked by means of a connecting rod to a transverse link bar pivotally mounted on the second profiles of the two slide rails and which comprises a support flange co-operating with the latch of the second slide rail to move said latch of the second slide rail into its unlocked position on actuation of the second control means.